Histories of major depressive disorder (MDD) are more prevalent in Premenstrual Dysphoric Disorder (PMDD), and both disorders are associated with greater daily stress and somatic symptoms. We will compare PMDD (N=26) and non-PMDD women (N=26), with or without a history of MDD (N=13 per each MDD x PMDD group), for experimental pain sensitivity and biological responses to stress in order to examine biological factors contributing to somatic symptoms in these disorders. This study will examine sympathetic and hypothalamic-pituitary-adrenal (HPA) axis responses to stress, experimental and daily pain ratings, as well as the relationship between biological pain regulatory mechanisms, (e.g. blood pressure) and experimental pain sensitivity in the luteal phase of the menstrual cycle. Testing will involve 3 components: 1) Daily ratings of mood and somatic symptoms; 2) Experimental pain sensitivity to ischemic forearm pain; 3) Blood pressure, heart rate, and plasma norepinephrine, cortisol, and beta-endorphins at rest and in response to mental stress. The results of this study will provide insight into stress responsive biological factors that may contribute to heightened pain in both PMDD and MDD, and may confirm other evidence for persistent stress dysregulation in currently euthymic women with prior MDD. MDD affects approximately 25 percent of women in their lifetime, while PMDD affects 5-8 percent of women in their reproductive years. The impact of PMDD on quality of life is equivalent to that seen in MDD and other psychiatric disorders. Studies designed to address biological factors involved in the somatic symptoms of both MDD and PMDD may have implications for treatment of these disorders. [unreadable] [unreadable] [unreadable]